Androgen receptor-mediated inhibition of estrogen-induced uterine peroxidase.

Flutamide, an anti-androgen known to act through the androgen receptor, abolished the inhibitory action of testosterone on the induction of peroxidase in immature rat uteri without affecting inhibition produced by progesterone. The time course of the androgen effect on estrogen-induced uterine peroxidase, uterine weight and glucose 6-phosphate dehydrogenase activity was also determined together with the effect of flutamide on these steroid hormone-sensitive parameters. The possible mechanism of action of these compounds is discussed, particularly in the light of estrogen-induced eosinophilia. It is proposed that the observed interaction between testosterone and estradiol is mediated through their own specific receptors and not by illicit occupation of the estrogen receptor by the androgen. 5-Androstene-3 beta, 17 beta-diol (Adiol), an androgen known to exert estrogenic effects through the estrogen receptor, induced uterine peroxidase and was without significant effect on the action of estradiol, in contrast to testosterone.